Lumbar disc degeneration: epidemiology and genetic influences

Adjacent segment degeneration after single-segment PLIF: the risk factor for degeneration and its impact on clinical outcomes

PURPOSE

To investigate: (1) the risk factors for radiologic cranial adjacent segment degeneration (ASD) after single-segment PLIF at the same level, and (2) the impact of the ASD on the clinical outcomes.

METHODS

From October 2004 to May 2009, 109 patients who underwent PLIF for degenerative instability at L4/5 and have more than 2 years follow-up were studied retrospectively. We measured the preoperative bone mineral density (BMD), lumbar lordosis, the lumbosacral joint angle, the lumbar inclination, the height and the dynamic angulation of the intervertebral space at the fused segments and the upper adjacent segment, the sliding displacement between L3 and L4. Clinical outcomes were evaluated using the Japanese Orthopedic Association (JOA) score and the Oswestry Disability Index (ODI). Patients were divided into two groups according to the progression of L3-L4 degeneration: Group A without progression of L3-L4 degeneration, Group B with progression of L3-L4 degeneration. Clinical outcomes and radiologic measurement index between the two groups were compared, and the risk factors for progression of L3-L4 degeneration were analyzed. The correlation between clinical outcomes and progression of L3-L4 degeneration were also investigated.

RESULTS

There were 11 patients (22%) classified into Group A. No significant difference was found between the two groups in terms of the lordosis angle at L1 and S1, the laminar inclination at L3, the pre-existing L3-L4 disk degeneration, the lordosis angle of L4-L5, the lumbosacral joint angle and preoperative BMD (P > 0.05). Significant differences were found between the two groups in age. No significant difference was found between the two groups in the ODI and the JOA score at the final follow-up (P > 0.05).

CONCLUSION

Radiologic degeneration of the cranial adjacent segment after single-segment PLIF did not significantly correlate with clinical outcomes. Age was a risk factor for radiologic degeneration, however, there was no significant correlation between degeneration and preoperative radiologic factors and bone mineral density (BMD).

Phylogeny of the southern Plateau: an osteometric evaluation of inter-tribal relations

This project focuses on whether determination of physical differences among closely affiliated Native American populations inhabiting the southern Plateau is possible. The study includes 318 individuals and approximately 100 recorded measurements of the cranium, humerus, femur, and tibia of each individual. The compiled measurements were evaluated in terms of their implied genetic affiliation, environmental location, and cultural identity. Along with metric measurements, pathological conditions were also compared to provide a control experiment to confirm or reject the findings. The results indicate that there are slight differences detectable among the populations as a result of environmental and European contact factors. The most apparent disparities are seen in relation to the size and shape of the lower extremities, which are highly associated with environmental and dietary stress. Pathological analysis supports the findings of the osteological analysis, suggesting that if the location of the burial and a general time period for interment are known, cultural identification is possible.

Adolescent disc dysplasia and back pain

PURPOSE

Adolescent disc dysplasia can be a cause of significant back pain and functional impairment in patients. We present a case series of patients inflicted with adolescent disc dysplasia (ADD).

METHODS

A retrospective search was performed identifying patients presenting with ADD. Radiographic studies and advanced imaging were described. We documented presenting symptoms and clinical course.

RESULTS

Six patients were identified. All patients presented with mechanical back pain, which worsened with flexion and extension. Magnetic resonance imaging was most accurate imaging modality.

CONCLUSION

Among our patient cohort, treatment for adolescent disc dysplasia consisted of a combination of physical therapy and bracing. Neither approach proved to be very effective, with only one patient asymptomatic at follow-up.

On total disc replacement

Low back pain consumes a large part of the community's resources dedicated to health care and sick leave. Back disorders also negatively affect the individual leading to pain suffering, decreased quality-of-life and disability. Chronic low back pain (CLBP) due to degenerative disc disease (DDD) is today often treated with fusion when conservative treatment has failed and symptoms are severe. This treatment is as successful as arthroplasty is for hip arthritis in restoring the patient's quality of life and reducing disability. Even so, there are some problems with this treatment, one of these being recurrent CLBP from an adjacent segment (ASD) after primarily successful surgery. This has led to the development of alternative surgical treatments and devices that maintain or restore mobility, in order to reduce the risk for ASD. Of these new devices, the most frequently used are the disc prostheses used in Total Disc Replacement (TDR). This thesis is based on four studies comparing total disc replacement with posterior fusion. The studies are all based on a material of 152 patients with DDD in one or two segments, aged 20-55 years that were randomly treated with either posterior fusion or TDR. The first study concerned clinical outcome and complications. Follow-up was 100% at both one and two years. It revealed that both treatment groups had a clear benefit from treatment and that patients with TDR were better in almost all outcome scores at one-year follow-up. Fusion patients continued to improve during the second year. At two-year follow-up there was a remaining difference in favour of TDR for back pain. 73% in the TDR group and 63% in the fusion group were much better or totally pain-free (n.s.), while twice as many patients in the TDR group were totally pain free (30%) compared to the fusion group (15%). Time of surgery and total time in hospital were shorter in the TDR group. There was no difference in complications and reoperations, except that seventeen of the patients in the fusion group were re-operated for removal of their implants. The second study concerned sex life and sexual function. TDR is performed via an anterior approach, an approach that has been used for a long time for various procedures on the lumbar spine. A frequent complication reported in males when this approach is used is persistent retrograde ejaculation. The TDR group in this material was operated via an extra-peritoneal approach to the retroperitoneal space, and there were no cases of persistent retrograde ejaculation. There was a surprisingly high frequency of men in the fusion group reporting deterioration in ability to have an orgasm postoperatively. Preoperative sex life was severely hampered in the majority of patients in the entire material, but sex life underwent a marked improvement in both treatment groups by the two-year follow-up that correlated with reduction in back pain. The third study was on mobility in the lumbar spinal segments, where X-rays were taken in full extension and flexion prior to surgery and at two-year follow-up. Analysis of the films showed that 78% of the patients in the fusion group reached the surgical goal (non-mobility) and that 89% of the TDR patients maintained mobility. Preoperative disc height was lower than in a normative database in both groups, and remained lower in the fusion group, while it became higher in the TDR group. Mobility in the operated segment increased in the TDR group postoperatively. Mobility at the rest of the lumbar spine increased in both treatment groups. Mobility in adjacent segments was within the norm postoperatively, but slightly larger in the fusion group. In the fourth study the health economics of TDR vs Fusion was analysed. The hospital costs for the procedure were higher for patients in the fusion group compared to the TDR group, and the TDR patients were on sick-leave two months less. In all, these studies showed that the results in the TDR group were as good as in the fusion group. Patients are more likely to be totally pain-free when treated with TDR compared to fusion. Treatment with this new procedure seems justified in selected patients at least in the short-term perspective. Long-term follow-up is underway and results will be published in due course.

The accuracy of the physical examination for the diagnosis of midlumbar and low lumbar nerve root impingement

STUDY DESIGN

Cross-sectional study with prospective recruitment. OBJECTIVE.: To determine the accuracy of the physical examination for the diagnosis of midlumbar nerve root impingement (L2, L3, or L4), low lumbar nerve root impingement (L5 or S1) and level-specific lumbar nerve root impingement on magnetic resonance imaging, using individual tests and combinations of tests.

SUMMARY OF BACKGROUND DATA

The sensitivity and specificity of the physical examination for the localization of nerve root impingement has not been previously studied.

METHODS

Sensitivities, specificities, and likelihood ratios (LRs) were calculated for the ability of individual tests and test combinations to predict the presence or absence of nerve root impingement at midlumbar, low lumbar, and specific nerve root levels.

RESULTS

LRs ≥5.0 indicate moderate to large changes from pre-test probability of nerve root impingement to post-test probability. For the diagnosis of midlumbar impingement, the femoral stretch test (FST), crossed FST, medial ankle pinprick sensation, and patellar reflex testing demonstrated LRs ≥5.0 (LR ∞). LRs ≥5.0 were observed with the combinations of FST and either patellar reflex testing (LR 7.0; 95% confidence interval [CI] 2.3-21) or the sit-to-stand test (LR ∞). For the diagnosis of low lumbar impingement, the Achilles reflex test demonstrated an LR ≥5.0 (LR 7.1; 95% CI 0.96-53); test combinations did not increase LRs. For the diagnosis of level-specific impingement, LRs ≥5.0 were observed for anterior thigh sensation at L2 (LR 13; 95% CI 1.8-87); FST at L3 (LR 5.7; 95% CI 2.3-4.4); patellar reflex testing (LR 7.7; 95% CI 1.7-35), medial ankle sensation (LR ∞), or crossed FST (LR 13; 95% CI 1.8-87) at L4; and hip abductor strength at L5 (LR 11; 95% CI 1.3-84). Test combinations increased LRs for level-specific root impingement at the L4 level only.

CONCLUSION

Individual physical examination tests may provide clinical information that substantially alters the likelihood that midlumbar impingement, low lumbar impingement, or level-specific impingement is present. Test combinations improve diagnostic accuracy for midlum-bar impingement.

Heparanase isoform expression and extracellular matrix remodeling in intervertebral disc degenerative disease

OBJECTIVE

To determine the molecules involved in extracellular matrix remodeling and to identify and quantify heparanase isoforms present in herniated and degenerative discs.

INTRODUCTION

Heparanase is an endo-beta-glucuronidase that specifically acts upon the heparan sulfate chains of proteoglycans. However, heparanase expression in degenerative intervertebral discs has not yet been evaluated. Notably, previous studies demonstrated a correlation between changes in the heparan sulfate proteoglycan pattern and the degenerative process associated with intervertebral discs.

METHODS

Twenty-nine samples of intervertebral degenerative discs, 23 samples of herniated discs and 12 samples of non-degenerative discs were analyzed. The expression of both heparanase isoforms (heparanase-1 and heparanase-2) was evaluated using immunohistochemistry and real-time RT-PCR analysis.

RESULTS

Heparanase-1 and heparanase-2 expression levels were significantly higher in the herniated and degenerative discs in comparison to the control tissues, suggesting a possible role of these proteins in the intervertebral degenerative process.

CONCLUSION

The overexpression of heparanase isoforms in the degenerative intervertebral discs and the herniated discs suggests a potential role of both proteins in the mediation of inflammatory processes and in extracellular matrix remodeling. The heparanase-2 isoform may be involved in normal metabolic processes, as evidenced by its higher expression in the control intervertebral discs relative to the expression of heparanase-1.

Recurrent adjacent segment disease and cauda equina syndrome

PURPOSE

A case of cauda equina lesion as a result of recurrent adjacent segment degeneration (ASD) after multiple lumbar fusions is reported. ASD might be a consequence of biomechanical overload or simply a normal degenerative process. The reported clinical relevance of ASD is rather low. We describe an unusual case of cauda equina compression at L1-L2 in a patient who had undergone L2-L4 fusion 8 years previously and 2 decompression-fusion surgeries 16 years before.

MATERIALS AND METHODS

A 72-year-old man, who had two previous lumbar fusion-decompression procedures, underwent a third lumbar surgery in December 2000 to treat symptomatic spinal canal stenosis associated with L3-L4 pseudoarthrosis. After a symptom-free period of 8 years, the patient experienced low back pain radiating to both legs while standing, associated with saddle sensory disturbances and incontinence. Physical examination ruled out significant motor deficits. Plain radiographs showed solid fusion from L2 to L4, good spinal alignment, and low-grade L1-L2 retrolisthesis. Stainless steel pedicular instrumentation distorted magnetic resonance imaging, preventing adequate spinal canal evaluation. Electromyography demonstrated signs of cauda equina compression (bilateral L3-S2). CT myelography showed a stop at L1-L2, due to a severe spinal canal stenosis. L1-L2 decompression and fusion were performed.

RESULTS

After an uneventful surgery with no complications, the symptoms abated and incontinence recovered.

CONCLUSIONS

Even if the reported clinical relevance of ASD is very low, fused patients with a constitutional narrow spinal canal are at risk of developing severe neural compression at the level adjacent to the fusion.

Healing of a painful intervertebral disc should not be confused with reversing disc degeneration: implications for physical therapies for discogenic back pain

BACKGROUND

Much is known about intervertebral disc degeneration, but little effort has been made to relate this information to the clinical problem of discogenic back pain, and how it might be treated.

METHODS

We re-interpret the scientific literature in order to provide a rationale for physical therapy treatments for discogenic back pain.

INTERPRETATION

Intervertebral discs deteriorate over many years, from the nucleus outwards, to an extent that is influenced by genetic inheritance and metabolite transport. Age-related deterioration can be accelerated by physical disruption, which leads to disc "degeneration" or prolapse. Degeneration most often affects the lower lumbar discs, which are loaded most severely, and it is often painful because nerves in the peripheral anulus or vertebral endplate can be sensitised by inflammatory-like changes arising from contact with blood or displaced nucleus pulposus. Surgically-removed human discs show an active inflammatory process proceeding from the outside-in, and animal studies confirm that effective healing occurs only in the outer anulus and endplate, where cell density and metabolite transport are greatest. Healing of the disc periphery has the potential to relieve discogenic pain, by re-establishing a physical barrier between nucleus pulposus and nerves, and reducing inflammation.

CONCLUSION

Physical therapies should aim to promote healing in the disc periphery, by stimulating cells, boosting metabolite transport, and preventing adhesions and re-injury. Such an approach has the potential to accelerate pain relief in the disc periphery, even if it fails to reverse age-related degenerative changes in the nucleus.

Effects of etiology on inpatient rehabilitation outcomes in 65- to 74-year-old patients with incomplete paraplegia from a nontraumatic spinal cord injury

OBJECTIVE

To examine differences in rehabilitation outcomes for older patients with a nontraumatic spinal cord injury (NT-SCI) for 5 etiologic diagnoses: degenerative spinal disease (DSD), malignant spinal tumor, benign spinal tumor, vascular ischemia, and spinal abscess.

DESIGN

Retrospective cohort study that used Medicare claims and assessment data.

SETTING

A total of 479 inpatient rehabilitation hospitals and units.

PATIENTS

A total of 1780 Medicare beneficiaries (65-74 years old) with incomplete paraplegia attributable to NT-SCI who were discharged from inpatient rehabilitation facilities from 2002 through 2005.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Length of stay, discharge Functional Independence Measure (FIM) instrument motor item and subscale scores, and discharge destination.

RESULTS

Demographic characteristics varied by etiology group. Mean +/- SD rehabilitation stays ranged from 13.3 +/- 7.7 days for DSD to 26.4 +/- 13.4 days for vascular ischemia. Adjusted data showed stays differed (P < .001) across etiology groups. Adjusted discharge mean self-care and mobility subscores revealed that patients with DSD and benign tumor were more independent (P < .001) than patients with a malignant tumor or spinal abscess. Patients with vascular ischemia were more dependent (P < .01) in mobility than the DSD and benign tumor groups. Etiologic differences (P < .01) in independence in discharge FIM modifiers for walking (FIM > or = 4), bladder (FIM > or = 6) and bowel management (FIM > or = 6) and bowel accidents/continence (FIM > or = 6), but not bladder accidents (FIM > or = 6), were present. The percent of patients discharged to a community residence ranged from 59.3% to 92.6%. Adjusted data showed that significantly larger percentages (P < .01) of patients in the DSD and malignant tumor groups than in the spinal abscess group were discharged to a community residence (versus nursing home).

CONCLUSION

There are etiologic differences in demographics, rehabilitation length of stay, functional outcomes, and discharge destination in elderly patients with NT-SCI.

[Pedicle screw-based systems for dynamic stabilization : An insight into the philosophy, technique, indications and success of these systems]

Pedicle screw-based dorsal dynamic systems for segmental stabilization of the lumbar spine are an addition to established surgical methods. They differ in terms of their kinetics as well as their materials. The long-term load on these systems is much higher than in spondylodesis systems, which can only successfully bear loads until bone fusion; cases of implant failure and screw loosening are not rare.Pedicle screw-based systems represent a therapeutic option when conservative treatment proves unsuccessful and fusion seems to be too early. Finding the correct indication versus that of established methods is complex given our limited knowledge to date; symptomatic segments with moderate degenerative changes in facet joints and disc height, as well as Modic 2-3 signs seem to be appropriate cases. The same is true of segments adjacent to planned fusions. Dynamic stabilization can be considered in the case of long fusion, cranial location in the lumbar spine and high likelihood of instability and deformity.

Nanostructure of collagen fibrils in human nucleus pulposus and its correlation with macroscale tissue mechanics

Collagen fibrils are the main structural components of the nucleus pulposus tissue in the intervertebral discs. The structure-property relationship of the nucleus pulposus (NP) tissues is still unclear. We investigated the structure of individual collagen fibrils of the NP and evaluated its correlation with the bulk mechanical properties of the tissue. Collagen fibrils were extracted from the NP of discs retrieved from adolescents during scoliosis correction surgery, and the extracts were confirmed by SDS-PAGE. The diameters of the individual collagen fibrils were measured through atomic force microscopy, and the compressive mechanical properties of the tissues were evaluated by confined compression. The correlations between the nanoscale morphology of the collagen fibrils and the macroscale mechanical properties of the tissues were evaluated by linear regression. The SDS-PAGE results showed that the fibril extracts were largely composed of type II collagen. The mean diameter of the collagen fibrils was 92.1 +/- 26.54 nm; the mean swelling pressure and compressive modulus of the tissues were 6.15 +/- 4.3 kPa and 1.23 +/- 0.7 MPa, respectively. The mean fibril diameter had no linear correlation (R(2) = 0.30) with the swelling pressure of the tissues. However, it had a mild linear correlation with the compressive modulus (p = 0.023, R(2) = 0.68). This is the first study, to our knowledge, to evaluate the nanostructure of the individual collagen fibrils of the nucleus pulposus and its relationship with macroscale mechanical properties of the NP tissues.

Immunohistochemical Analysis of Osteoblasts in Zygapophyseal Joints of Patients with Ankylosing Spondylitis Reveal Repair Mechanisms Similar to Osteoarthritis

Objective.

New bone formation of the spine is a typical feature of ankylosing spondylitis (AS). It is unknown whether new bone formation is part of a physiological repair process or a unique pathological entity of the disease.

Methods.

We analyzed zygapophyseal joints from patients with AS and osteoarthritis (OA) undergoing spinal surgery for rigid hyperkyphosis (AS) or radiculopathy caused by severe OA. In 17 patients with AS, 11 with OA, and 5 controls we performed immunohistochemical analysis of osteoprotegerin (OPG), nuclear factor-κB ligand (RANKL), and osteocalcin (OC) expression in osteoblasts and determined the trabecular thickness in AS and OA patients and controls. Osteoclasts were detected by tartrate-resistant alkaline phosphatase (TRAP) staining.

Results.

Trabecular thickness was significantly lower in patients with AS compared to OA (p = 0.01). The absolute number of CD56+ osteoblasts (p < 0.001) and OC+ (p = 0.002), OPG+ (p = 0.003), and RANKL+ osteoblasts (p = 0.03) in AS patients was also significantly lower than in OA patients. The percentages of OC+, OPG+, and RANKL+ osteoblasts did not differ between AS and OA (p > 0.05 in all cases). In controls, the percentages of OPG+ (p = 0.013) and OC+ (p = 0.034) but not RANKL+ (p > 0.05) osteoblasts were significantly lower compared to AS patients. The frequency of TRAP+ osteoclasts in AS patients was significantly lower compared to OA (p < 0.001), but higher compared to controls.

Conclusion.

Immunohistochemical analysis of zygapophyseal joints suggested that osteoblast activity is similar in AS and OA, indicating that new bone formation is possibly a physiological function of repair in both diseases.

Segment-by-segment stabilization for degenerative disc disease: a hybrid technique

Patients with multisegmental degenerative disc disease (DDD) resistant to conservative therapy are typically treated with either fusion or non-fusion surgical techniques. The two techniques can be applied at adjacent levels using Dynesys (Zimmer GmbH, Winterthur, Switzerland) implants in a segment-by-segment treatment of multiple level DDD. The objective of this study was to evaluate the clinical and radiological outcome of patients treated using this segment-by-segment application of Dynesys in some levels as a non-fusion device and in other segments in combination with a PLIF as a fusion device. A consecutive case series is reported. The sample included 16 females and 15 males with a mean age of 53.6 years (range 26.3-76.4 years). Mean follow-up time was 39 months (range 24-90 months). Preoperative Oswestry disability index (ODI), back- and leg-pain scores (VAS) were compared to postoperative status. Fusion success and system failure were assessed by an independent reviewer who analyzed AP and lateral X-rays. Back pain improved from 7.3 +/- 1.7 to 3.4 +/- 2.7 (p < 0.000002), leg pain from 6.0 +/- 2.9 to 2.3 +/- 2.9 (p < 0.00006), and ODI from 51.6 +/- 13.2% to 28.7 +/- 18.0% (p < 0.00001). Screw loosening occurred in one of a total of 222 implanted screws (0.45%). The results indicate that segment-by-segment treatment with Dynesys in combination with interbody fusion is technically feasible, safe, and effective for the surgical treatment of multilevel DDD.

Correlations between radiographic, magnetic resonance and histological examinations on the degeneration of human lumbar intervertebral discs

CONTEXT AND OBJECTIVE

There is controversy regarding which imaging method is best for identifying early degenerative alterations in intervertebral discs. No correlations between such methods and histological finds are presented in the literature. The aim of this study was to correlate the thickness of intervertebral discs measured on simple radiographs with the degree of degeneration seen on magnetic resonance images and the histological findings relating to nerve ends inside the discs.

DESIGN AND SETTING

Cross-sectional correlation study on the lumbar spines of human cadavers, at Universidade Federal de São Paulo (Unifesp), São Paulo, Brazil.

METHODS

Ten lumbar spinal columns were extracted from human cadavers and subjected to magnetic resonance imaging and simple radiography. They were classified according to the degree of disc degeneration seen on magnetic resonance, and the thickness of the discs was measured on radiographs. The intervertebral discs were then extracted, embedded in paraffin and analyzed immunohistochemically with protein S100, and the nerve fibers were counted and classified.

RESULTS

No correlation was observed between the thickness of the intervertebral discs and the degree of degeneration seen on magnetic resonance images. Only the uppermost lumbar discs (L1/L2 and L2/L3) presented a correlation between their thickness and type I and IV nerve endings.

CONCLUSION

Reduced disc thickness is unrelated to increased presence of nerve ends in intervertebral discs, or to the degree of disc degeneration.

Risk factors for lumbar intervertebral disc herniation in Chinese population: a case-control study

STUDY DESIGN

A case-control study of 4180 subjects was carried.

OBJECTIVE

To explore the risk factors of lumbar disc herniation in China.

SUMMARY OF BACKGROUND DATA

In China, along with the economic development, people's living environment and working conditions have undergone some tremendous changes, such as the accelerating life pace and competition. In this situation, it is important to know whether the risk factors of lumbar disc herniation have changed or not. This case-control study, including the possible social and psychological factors based on the literature, attempted to search the new risk factor, therefore provide better prevention measures for lumbar disc herniation.

METHODS

A total of 2010 hospitalized patients, diagnosed with lumbar disc protrusion by CT and/or MRI were selected as cases. A total of 2070 people from communities and hospitals, without history of low back pain and sciatica, were selected as controls. All patients and controls were investigated for their family history, occupational characters' smoking status, working psychosocial factors, etc. The risk factors were analyzed by multiple nonconditional logistic regression method.

RESULTS

Family history (OR = 3.6) was the most important risk factor for lumbar disc protrusion in this study, followed by lumbar load (OR = 2.1), hard-working (OR = 1.8), and time urgency (OR = 1.1). Additionally, physical exercises (OR = 0.5) and bed characteristics (OR = 0.4) appeared to be the protective factors for lumbar disc protrusion. After stratified by age, family history (OR = 14.5), occupational character (OR = 5.2), and physical exercises (OR = 0.2) stronger association with lumbar disc protrusion was seen in subjects younger than 30 years. In subjects from 30 to 55 years, family history (OR = 5.1), lumbar load (OR = 1.91), hard-working (1.9), physical exercises (OR = 0.5), time urgency (OR = 1. 3), bed characteristics (OR = 0.4) were significantly important. In subjects older than 55 years, lumbar load (OR = 2.9) and bed characteristics (OR = 0.4) were closely related to lumbar disc protrusion.

CONCLUSION

Family history, lumbar load, hard-working, and time urgency are the major risk factors for lumbar disc herniation, and physical exercises and sleeping on the hard bed might be the protective factors.

Magnetic resonance imaging findings of the lumbar spine in elite horseback riders: correlations with back pain, body mass index, trunk/leg-length coefficient, and riding discipline

BACKGROUND

Most orthopaedic problems experienced by competitive horseback riders are related to pain in the lower back, hip joint, and hamstring muscles. Riders-especially, show jumpers-are frequently hampered in their performance because of lumbar pain. To date, there has been no research into lumbar disk degeneration in elite competitive riders.

HYPOTHESIS

Competitive horseback riding accelerates lumbar disk degeneration.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Fifty-eight elite riders (18 men, 40 women; mean age, 32.4 years) and a control group of 30 nonriding volunteers (17 men, 13 women; mean age, 28.7 years) were evaluated for lumbar disk degeneration, cross-sectional area of paraspinal muscles, spondylolysis, and spondylolisthesis, using magnetic resonance imaging (MRI). The prevalence of disk degeneration between the 2 groups was compared, and the relationship was investigated between low back pain (LBP), riding discipline, body mass index (BMI), trunk/leg-length coefficient, and MRI results.

RESULTS

Eighty-eight percent of elite riders (n = 51) had a history of LBP, versus 33% of the controls (P < .05). There was no statistical difference for the prevalence of LBP among the different riding disciplines. However, there was a high rate of pathologic T2 signal intensity of the lumbar intervertebral disk among riders-specifically, dressage riders-yet no significant increase when compared with controls. History of LBP symptoms, riding discipline, BMI, and trunk/leg-length ratio had no significant effect on the development of lumbar disk degeneration. Occult fractures of the pars interarticularis and manifest spondylolysis were not seen for any rider. Two controls had spondylolisthesis Meyerding grade 1 not associated with back pain.

CONCLUSION

Although riders have a high prevalence of LBP, there is no conclusive MRI evidence to suggest that the cause lies in undue disk degeneration, spondylolysis, spondylolisthesis, or pathologic changes of the paraspinal muscles of the lumbar spine.

Dynamic bulging of intervertebral discs in the degenerative lumbar spine

STUDY DESIGN

The effect of postural change on degenerative lumbar discs was quantified using novel kinematic magnetic resonance imaging (kMRI).

OBJECTIVE

The purpose is to describe the bulging of degenerative intervertebral lumbar discs in vivo subjected to different postural loads using a novel kMRI.

SUMMARY OF BACKGROUND DATA

Symptomatic lumbar disc degeneration is a leading cause of pain and disability throughout the world. Over 70% of US citizens will experience a debilitating episode of low back pain. Earlier reports of degenerative disc changes are cadaver studies or are performed with recumbent MRI that eliminates the functional effects of gravity and muscle power. Little data are available on the behavior of degenerative intervertebral discs in vivo under physiologic loads.

METHODS

A total of 513 patients obtained kMRI. Disc bulging beyond the intervertebral space was quantified during upright neutral, flexion, and extension imaging. The degree of intervertebral disc degeneration was correlated using the Pfirrmann Classification.

RESULTS

Moderately degenerated intervertebral discs (grade III and IV) demonstrated greater bulging than mildly degenerated discs (grade II). Severely degenerated discs (grade V) also showed a trend toward greater bulging, but this was not significant. Grade I discs at all levels moved posteriorly in flexion and anteriorly in extension when compared to neutral posture. However, mild to severe (grade II-V) degenerative discs behaved differently in response to postural loads. Extension resulted in significant posterior bulging, while flexion did not demonstrate obvious anterior derangement.

CONCLUSION

Disc bulging increases with the severity of disc degeneration. Grade I discs demonstrate the expected sagittal migration in response to postural load. However, more degenerative discs behave less predictably, and spine extension may result in significant posterior disc bulging. Degenerative changes in the intervertebral disc significantly affect the kinematic patterns under postural load in vivo. kMRI is a useful tool to quantify the kinematic behavior of degenerative intervertertebral discs.

Decreased physical function and increased pain sensitivity in mice deficient for type IX collagen

OBJECTIVE

In mice with Col9a1 gene inactivation (Col9a1(-/-)), osteoarthritis (OA) and intervertebral disc degeneration develop prematurely. The aim of this study was to investigate Col9a1(-/-) mice for functional and symptomatic changes that may be associated with these pathologies.

METHODS

Col9a1(-/-) and wild-type mice were investigated for reflexes, functional impairment (beam walking, pole climbing, wire hang, grip strength), sensorimotor skills (rotarod), mechanical sensitivity (von Frey hair), and thermal sensitivity (hot plate/tail flick). Gait was also analyzed to determine velocity, stride frequency, symmetry, percentage stance time, stride length, and step width. Postmortem, sera obtained from the mice were analyzed for hyaluronan, and their knees and spines were graded histologically for degeneration.

RESULTS

Col9a1(-/-) mice had compensatory gait changes, increased mechanical sensitivity, and impaired physical ability. Col9a1(-/-) mice ambulated with gaits characterized by increased percentage stance times and shorter stride lengths. These mice also had heightened mechanical sensitivity and were deficient in contact righting, wire hang, rotarod, and pole climbing tasks. Male Col9a1(-/-) mice had the highest mean serum hyaluronan levels and strong histologic evidence of cartilage erosion. Intervertebral disc degeneration was also detected, with Col9a1(-/-) mice having an increased incidence of disc tears.

CONCLUSION

These data describe a Col9a1(-/-) behavioral phenotype characterized by altered gait, increased mechanical sensitivity, and impaired function. These gait and functional differences suggest that Col9a1(-/-) mice select locomotive behaviors that limit joint loads. The nature and magnitude of behavioral changes were largest in male mice, which also had the greatest evidence of knee degeneration. These findings suggest that Col9a1(-/-) mice present behavioral changes consistent with anatomic signs of OA and intervertebral disc degeneration.

Intervertebral disc repair using adipose tissue-derived stem and regenerative cells: experiments in a canine model

STUDY DESIGN

Therapeutic treatment of intervertebral disc repair using cells.

OBJECTIVE

The goal of the study was to test the hypothesis that repair of a damaged disc is possible using autologous adipose tissue derived stem and regenerative cells (ADRCs).

SUMMARY OF BACKGROUND DATA

Degradation resulting from either acute or chronic repetitive disc injury leads to disc degeneration. However, if a damaged disc could be repaired in the early stages, before the onslaught of degradation, then the disc degeneration process may be slowed down.

METHODS

Twelve dogs underwent a partial nucleotomy at 3 lumbar levels (L3-L4, L4-L5, and L5-L6); adjacent levels served as nonoperated controls. The animals (or discs) were allowed to recover from the surgery for 6 weeks. At that time subcutaneous adipose tissue was harvested and ADRCs were isolated. The 3 experimental discs that had undergone a partial nucleotomy were randomized to receive: (1) ADRCs in hyaluronic acid carrier (Cells/HA); (2) HA only; or (3) No Intervention. Assessments of the 3 experimental discs plus the 2 adjacent untouched discs were made using MRI, radiography, histology, and biochemistry. The animals were killed at 6 months and at 12 months.

RESULTS

Repair in this study was specifically demonstrated through histology and biochemical analysis. Disc levels receiving ADRCs more closely resembled the healthy controls as evidenced in matrix translucency, compartmentalization of the anulus, and in cell density within the nucleus pulposus. Matrix analysis for Type-II collagen and aggrecan demonstrated evidence of a statistically better regenerative stimulation to the disc provided by ADRCs when compared to either the HA only or no intervention treatments.

CONCLUSION

Autologous adipose tissue derived stem and regenerative cells, as used in this disc injury model, were effective in promoting disc regeneration, as evidenced by disc matrix production and overall disc morphology.

Associação entre espondiloartrose lombar e trabalho pesado

OBJETIVO: Estudar uma possível associação entre espondiloartrose lombar e trabalho pesado. METODOLOGIA: Estudo epidemiológico transversal realizado no período de outubro/04 a outubro/05, baseado em casos atendidos por um hospital público de São Luís, MA, Brasil. Trabalhadores (1256) encaminhados ao serviço de ortopedia foram submetidos à História Ocupacional, Exame Físico Ortopédico e Radiografia de Coluna Lombar e Lombossacra em AP/P e Oblíqüa. Critérios de inclusão e exclusão selecionaram 456 trabalhadores de ambos os gêneros, na faixa etária de 28 a 48 anos. Estes foram agrupados, conforme sua ocupação, em trabalho pesado e não pesado e submetidos aos critérios diagnósticos de espondiloartrose lombar. RESULTADOS: A associação entre trabalho pesado e espondiloartrose lombar foi realizada através do cálculo da razão de prevalências, cujo resultado mostrou-se elevado, evidenciando uma possível associação. A interferência de outras variáveis como possível viés de confundimento, tais como idade, gênero e peso corporal (IMC), foram controladas na fase de análise de dados através do teste de Mantel-Haenzel. O resultado final mostrou que não houve interferência dessas variáveis. CONCLUSÕES: ESTE estudo indicou uma possível associação entre exposição a trabalho pesado e espondiloartrose lombar.

Magnetic resonance study of lumbar disks in female dancers

BACKGROUND

Previous imaging studies have shown that degenerative disk disease is more common in the competitive female gymnast than in asymptomatic nonathletic people of the same age training to any degree. However, results of exposure-discordant monozygotic and classic twin studies suggest that physical loading specific to occupation and sport has a relatively minor role in disk degeneration, beyond that of upright postures and routine activities of daily living.

HYPOTHESIS

Intensive, regular, and prolonged dancing causes strain on the lumbar spine and can trigger or accelerate the development of degenerative diskopathy.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Forty volunteer female dancers (20 ballet and 20 flamenco) aged between 18 and 31 years (mean = 24.2) underwent magnetic resonance imaging of the lumbar spine. They were compared against a control group of 20 women of the same age. A descriptive analysis was done, and the 2 groups were compared by contingency table analysis using the Pearson chi-square test complemented by an analysis of residuals. Results Nine of the 20 women (45%) in the control group had disk degeneration compared with 13 of the 40 (32.5%) women in the dancer group, with a chi-square of 0.897 (not significant). There were 12 degenerated disks of the 100 explored (12%) in the control group compared with 21 of the 200 explored (10.5%) in the dancer group (chi-square = 0.153; not significant).

CONCLUSION

Dancing cannot be considered a risk factor for lumbar disk degeneration in women.

CLINICAL RELEVANCE

The present study indicates that dancing has no negative effect on the development of degenerative diskopathy.

Effect of limited nutrition on in situ intervertebral disc cells under simulated-physiological loading

STUDY DESIGN

Whole ovine caudal intervertebral discs (IVD) were cultured in sufficient and limited nutrition under simulated-physiologic loading for 7 and 21 days.

OBJECTIVE

To study the effect of limited nutrition on disc cells embedded in their native tissue in short- and midterm whole organ disc culture.

SUMMARY OF BACKGROUND DATA

Nutrient-limited induction of disc cell death in vitro has been demonstrated and is believed to be a factor in disc degeneration. Nutrient-limited cell death and its consequences, as it relates to degeneration, have not been investigated in the intact IVD.

METHODS

Ovine IVDs with endplates were cultured for 7 and 21 days under simulated-physiologic loading, either in media with limited (2 g/L) or sufficient (4.5 g/L) glucose concentration. Cell viability, relative gene expression, newly synthesized chondroitin sulfate content, and matrix metalloproteinase (MMP) activity were measured after culture and compared to fresh tissue.

RESULTS

In sufficient glucose media, cell viability was maintained through 7 days to 21 days of culture. In limited glucose, it dropped significantly to 62% in the anulus fibrosus and to 56% in the nucleus pulposus after 7 days and remained so until 21 days (63% in the anulus fibrosus and 52% in the nucleus pulposus). No significant differences were found between culture conditions for relative gene expression, newly synthesized chondroitin sulfate and inactive and active forms of MMP13 and MMP7.

CONCLUSION

With this culture system, whole IVD explants could be maintained up to 21 days. Cell viability decreased to 50% to 60% under limited nutrition within days and remained so up to 3 weeks. The surviving cells did not compensate matrix production in this time frame.

Molecular MR imaging for the evaluation of the effect of dynamic stabilization on lumbar intervertebral discs

The dynamic stabilization of lumbar spine is a non-fusion stabilization system that unloads the disc without the complete loss of motion at the treated motion segment. Clinical outcomes are promising but still not definitive, and the long-term effect on instrumented and adjacent levels is still a matter of discussion. Several experiments have been devised in order to gain a better understanding of the effect of the device on the intervertebral disc. One of the hypotheses was that while instrumented levels are partially relieved from loading, adjacent levels suffer from the increased stress. But this has not been proved yet. The aim of this study was to investigate the long-term effect of dynamic stabilization in vivo, through the quantification of glycosaminoglycans (GAG) concentration within instrumented and adjacent levels by means of the delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) protocol. Ten patients with low back pain, unresponsive to conservative treatment and scheduled for Dynesys implantation at one to three lumbar spine levels, underwent the dGEMRIC protocol to quantify GAG concentration before and 6 months after surgery. Each patient was also evaluated with visual analog scale (VAS), Oswestry, Prolo, Modic and Pfirrmann scales, both at pre-surgery and at follow-up. Six months after implantation, VAS, Prolo and Oswestry scales had improved in all patients. Pfirrmann scale could not detect any change, while dGEMRIC data already showed a general improvement in the instrumented levels: GAG was increased in 61% of the instrumented levels, while 68% of the non-instrumented levels showed a decrease in GAG, mainly in the posterior disc portion. In particular, seriously GAG-depleted discs seemed to have the greatest benefit from the Dynesys implantation, whereas less degenerated discs underwent a GAG depletion. dGEMRIC was able to visualize changes in both instrumented and non-instrumented levels. Our results suggest that the dynamic stabilization of lumbar spine is able to stop and partially reverse the disc degeneration, especially in seriously degenerated discs, while incrementing the stress on the adjacent levels, where it induces a matrix suffering and an early degeneration.

Prevalence and pattern of lumbar magnetic resonance imaging changes in a population study of one thousand forty-three individuals

STUDY DESIGN

A cross-sectional population study of magnetic resonance imaging (MRI) changes. OBJECTIVE.: To examine the pattern and prevalence of lumbar spine MRI changes within a southern Chinese population and their relationship with back pain.

SUMMARY OF BACKGROUND DATA

Previous studies on MRI changes and back pain have used populations of asymptomatic individuals or patients presenting with back pain and sciatica. Thus, the prevalence and pattern of intervertebral disc degeneration within the population is not known.

METHODS

Lumbar spine MRIs were obtained in 1043 volunteers between 18 to 55 years of age. MRI changes including disc degeneration, herniation, anular tears (HIZ), and Schmorl's nodes were noted by 2 independent observers. Differences were settled by consensus. Disc degeneration was graded using Schneiderman's classification, and a total score (DDD score) was calculated by the summation of the Schneiderman's score for each lumbar level. A K-mean clustering program was used to group individuals into different patterns of degeneration.

RESULTS

Forty percent of individuals under 30 years of age had lumbar intervertebral disc degeneration (LDD), the prevalence of LDD increasing progressively to over 90% by 50 to 55 years of age. There was a positive correlation between the DDD score and low back pain. L5-S1 and L4-L5 were the most commonly affected levels. Apart from the usual patterns of degeneration, some uncommon patterns of degeneration were identified, comprising of subjects with skip level lesions (intervening normal levels) and isolated upper or mid lumbar degeneration.

CONCLUSION

LDD is common, and its incidence increases with age. In a population setting, there is a significant association of LDD on MRI with back pain.

Ultrastructure of inclusion bodies in annulus cells in the degenerating human intervertebral disc

The rough endoplasmic reticulum (rER) of the cell has an architectural editing function that checks whether protein structure and three-dimensional assembly have occurred properly prior to export of newly synthesized material out of the cell. If these have been faulty, the material is retained within the rER as an inclusion body. Inclusion bodies have been identified previously in chondrocytes and osteoblasts in chondrodysplasias and osteogenesis imperfecta. Inclusion bodies in intervertebral disc cells, however, have only recently been recognized. Our objectives were to use transmission electron microscopy to analyze more fully inclusion bodies in the annulus pulposus and to study the extracellular matrix (ECM) surrounding cells containing inclusion bodies. ECM frequently encapsulated cells with inclusion bodies, and commonly contained prominent banded aggregates of Type VI collagen. Inclusion body material had several morphologies, including relatively smooth, homogeneous material, or a rougher, less homogeneous feature. Such findings expand our knowledge of the fine structure of the human disc cell and ECM during disc degeneration, and indicate the potential utility of ultrastructural identification of discs with intracellular inclusion bodies as a screening method for molecular studies directed toward identification of defective gene products in degenerating discs.

Exercise for the primary, secondary and tertiary prevention of low back pain in the workplace: a systematic review

INTRODUCTION

Low back pain (LBP) is one of the most costly conditions to manage in occupational health. Individuals with chronic or recurring LBP experience difficulties returning to work due to disability. Given the personal and financial cost of LBP, there is a need for effective interventions aimed at preventing LBP in the workplace. The aim of this systematic review was to examine the effectiveness of exercises in decreasing LBP incidence, LBP intensity and the impact of LBP and disability.

METHODS

A comprehensive literature search of controlled trials published between 1978 and 2007 was conducted and a total of 15 studies were subsequently reviewed and analyzed.

RESULTS

There was strong evidence that exercise was effective in reducing the severity and activity interference from LBP. However, due to the poor methodological quality of studies and conflicting results, there was only limited evidence supporting the use of exercise to prevent LBP episodes in the workplace. Other methodological limitations such as differing combinations of exercise, study populations, participant presentation, workloads and outcome measures; levels of exercise adherence and a lack of reporting on effect sizes, adverse effects, and types of sub-groups, make it difficult to draw definitive conclusions on the efficacy of workplace exercise in preventing LBP.

CONCLUSIONS

Only two out of the 15 studies reviewed were high in methodological quality and showed significant reductions in LBP intensity with exercise. Future research is needed to clarify which exercises are effective and the dose-response relationships regarding exercise and outcomes.

Expression of proteinase-activated receptor-2 in the intervertebral disc

STUDY DESIGN

Immunohistochemical and biochemical analyses of proteinase-activated receptor-2 (PAR-2) in rat and human intervertebral discs (IVDs).

OBJECTIVES

To examine the expression and function of PAR-2 in rat IVD cells, and to determine if PAR-2 is expressed in human IVDs.

SUMMARY OF BACKGROUND DATA

PAR-2 is a G protein-coupled receptor that contributes to the regulation of inflammatory reactions and the pathophysiology of inflammatory diseases, including arthritis. The expression of PAR-2 in the IVD has not been determined.

METHODS

PAR-2 expression by rat IVD cells and tissues was examined using immunohistochemistry and western blot. Rat anulus fibrosus cells in monolayer culture were used to examine the biologic role of PAR-2 in vitro. The effect of PAR-2-activating peptide (PAR-2AP) on the catabolic cascade was assessed by western blot and real-time PCR. The expression of PAR-2 by human IVD tissues at different stages of degeneration was determined by immunohistochemical analyses.

RESULTS

PAR-2 was expressed by rat IVD cells and in both anulus fibrosus and nucleus pulposus tissues, PAR-2 expression was up-regulated by interleukin-1beta (IL-1beta). PAR-2AP significantly increased the release of IL-1beta into the medium. Although PAR-2AP had no direct effect on matrix metalloproteinase-3 (MMP-3) and MMP-13 mRNA levels, treatment with PAR-2AP significantly up-regulated the mRNA levels of a disintegrin and metalloproteinase with thrombospondin motif-4. The simultaneous administration of PAR-2AP and IL-1beta synergistically up-regulated the mRNA levels of a disintegrin and metalloproteinase with thrombospondin motif-4, MMP-3, and MMP-13. The expression of PAR-2 was identified in human IVD tissues. The number of PAR-2-expressing cells was significantly elevated in advanced stages of IVD degeneration compared with those in early stages of degeneration.

CONCLUSION

Our results demonstrate for the first time that IVD cells express PAR-2. The expression of PAR-2 is regulated by IL-1beta stimulation. PAR-2 activation accelerates the expression of matrix-degrading enzymes. PAR-2 may play an important role in the cytokine-mediated catabolic cascade and consequently may be involved in IVD degeneration.

The Twin Spine Study: contributions to a changing view of disc degeneration

BACKGROUND CONTEXT

Disc degeneration was commonly viewed over much of the last century as a result of aging and "wear and tear" from mechanical insults and injuries. Thus, prevention strategies and research in lumbar degenerative changes and associated clinical conditions focused largely on mechanical factors as primary causes using an "injury model." The Twin Spine Study, a research program on the etiology and pathogenesis of disc degeneration, has contributed to a substantial revision of this view of determinants of lumbar disc degeneration.

PURPOSE

To provide a review of the methods and findings of the Twin Spine Study project.

STUDY DESIGN/SETTING

Narrative review of the Twin Spine Study.

METHODS

The Twin Spine Study, which started in 1991, is a multidisciplinary, multinational research project with collaborators primarily in Canada, Finland, and the United States. The most significant investigations related to determinants of disc degeneration included occupational exposures, driving and whole-body vibration exposure, smoking exposure, anthropomorphic factors, heritability, and the identification of genotypes associated with disc degeneration.

RESULTS

Among the most significant findings were a substantial influence of heredity on lumbar disc degeneration and the identification of the first gene forms associated with disc degeneration. Conversely, despite extraordinary discordance between twin siblings in occupational and leisure-time physical loading conditions throughout adulthood, surprisingly little effect on disc degeneration was observed. Studies on the effects of smoking on twins with large discordance in smoking exposure demonstrated an increase in disc degeneration associated with smoking, but this effect was small. No evidence was found to suggest that exposure to whole-body vibration through motorized vehicles leads to accelerated disc degeneration in these well-controlled studies. More recent results indicate that the effect of anthropometric factors, such as body weight and muscle strength on disc degeneration, although modest, appear in this work to be greater than those of occupational physical demands. In fact, some indications were found that routine loading may actually have some benefits to the disc.

CONCLUSIONS

The once commonly held view that disc degeneration is primarily a result of aging and "wear and tear" from mechanical insults and injuries was not supported by this series of studies. Instead, disc degeneration appears to be determined in great part by genetic influences. Although environmental factors also play a role, it is not primarily through routine physical loading exposures (eg, heavy vs. light physical demands) as once suspected.

Lumbar intervertebral disk degeneration in athletes

BACKGROUND

Several studies have reported that physical loading related to competitive sports activities is associated with lumbar intervertebral disk degeneration. However, the association between types of sports activities and disk degeneration has not been clarified.

HYPOTHESIS

The frequencies of disk degeneration may vary with the competitive sport because of the different postures and actions specific to each sport.

STUDY DESIGN

Cross-sectional study (prevalence); Level of evidence, 3.

METHODS

Study participants were 308 well-trained university athletes (baseball players, basketball players, kendo competitors, runners, soccer players, swimmers) and 71 nonathlete university students (reference group). Disk degeneration was evaluated using T2-weighted magnetic resonance imaging. A self-reported questionnaire concerning low back pain was also conducted.

RESULTS

The proportions of the participants who had disk degeneration among the baseball players (odds ratio, 3.23) and the swimmers (odds ratio, 2.95) were significantly higher than among the nonathletes using logistic regression analysis. When all patients were grouped together, the association between lifetime experience of low back pain and participants with disk degeneration was significant, and a linear association between the degree of severest low back pain experienced and participants with disk degeneration, analyzed by a Cochran-Mantel-Haenszel test, was also significant.

CONCLUSION

Continuous competitive baseball and swimming activities during youth may be associated with disk degeneration. Furthermore, the study indicates that the experience of severe low back pain might be a predictor of disk degeneration in youth. The authors hope that preventive measures and management to protect against disk degeneration and low back pain in athletes will be established by further studies based on these results.

RADIOLOGICAL ANALYSIS OF EXPERIMENTAL DISC DEGENERATION IN RABBITS

OBJECTIVE

To validate radiographic evaluation of a rabbit model for disc degeneration.

METHODS

Lumbar intervertebral discs of New Zealand rabbits were stabbed three times with a 18G needle at a limited depth of 5mm, through lateral approach. Serial radiographic images were taken on the early pre-and postoperative periods, and after four, eight and 12 weeks of the procedure, with subsequent analysis of disc height, osteophyte formation, endplate sclerosis, and presence of disc degeneration. The statistical analysis of data was validated by the Kappa coefficient, with a confidence interval (CI) of 95%.

RESULTS

A significant reduction of disc space was found on AP X-ray images after 12 postoperative weeks, with Kappa = 0.489 for CI 95% (0.25-0.72) with p < 0.001. X-ray signs of disc degeneration also presented Kappa = 0.63 for CI 95% (0.39-0.86) with p < 0.001. The remaining assessed criteria showed positive results, but with a lower Kappa value.

CONCLUSION

The disc degeneration model using rabbits as proposed in this study was shown to be feasible, with positive X-ray correlation between pre- and postoperative images, validating the potential to induce disc degeneration in this animal model for future studies.

The change in the diffusion of water in normal and degenerative lumbar intervertebral discs following joint mobilization compared to prone lying

STUDY DESIGN

Prospective, repeated measures obtained under treatment and control conditions.

OBJECTIVES

The purposes of this study were to provide preliminary evidence regarding the immediate change in the diffusion of water in the nuclear region of normal and degenerative lumbar intervertebral discs (IVDs) following a single session of lumbar joint mobilization, and to compare these findings to the immediate change in the diffusion of water following a 10-minute session of prone lying.

BACKGROUND

There is conflicting evidence regarding the effectiveness and efficacy of lumbar joint mobilization. Increased knowledge of the physiologic effects of lumbar joint mobilization can lead to refinement of its clinical application.

METHODS AND MEASURES

A total of 24 people (15 males and 9 females), ranging in age from 22 to 58 years, participated in this study. All subjects had a history of activity-limiting low back pain. Diffusion-weighted magnetic resonance images (DW-MRIs) were obtained immediately before and after a 10-minute session of lumbar joint mobilization. At least 1 month later, a second session was performed in which DW-MRIs were obtained immediately before and after a 10-minute session of prone lying.

RESULTS

Following lumbar joint mobilization, a significant increase (P = .002) in the mean values for diffusion of water was observed within degenerative IVDs at L5-S1 (22.2% increase; effect size, 0.97). Degenerative IVDs at L1-2 to L4-5 and normal IVDs at L1-2 to L5-S1 did not demonstrate a change in diffusion following joint mobilization. Prone lying was not associated with a change in diffusion for normal or degenerative IVDs.

CONCLUSIONS

The stimulus provided by lumbar joint mobilization may influence the diffusion of water in degenerative IVDs at L5-S1; however, these are preliminary findings and the relationship of these findings to pain and function needs further investigation.

Age- and pathology-specific measures of disc degeneration

STUDY DESIGN

: A measurement study.

OBJECTIVE

: To develop more accurate and specific measures of disc degeneration, which could better capture and distinguish systemic effects of aging and isolated disc irregularities using routine magnetic resonance imaging (MRI) and to examine their construct validity.

SUMMARY OF BACKGROUND DATA

: Knowledge of the etiopathogenesis of disc degeneration and pathology is fundamental to advancements in common spinal disorders. The quality of measures of disc degeneration is currently limited progress in this area.

METHODS

: Subjects were 519 twins, 35 to 70 years old, from a population-based cohort. Lumbar structures were traced and image software measured selected disc areas and T2 signal parameters of sagittal and axial images of lumbar spine with 1.5 Tesla MRI scanners. All signal measures were adjusted by adjacent cerebrospinal fluid signal. The mean adjusted disc signal, its standard deviation, and an irregularity measure were used to estimate the overall desiccation stage and signal variation across the disc. Associations with risk factors were examined to support or refute measurement validity.

RESULTS

: The signal-based measures introduced were highly reproducible (inter-rater reliability ICC = 0.95-1.00). Age explained more of the signal-based disc measures (AR2 = 16%-32%) than did the qualitative measures of disc degeneration in common use (AR2 = 3%-8%) in L1-L4 discs, supporting the validity of the new measures. The signal-based measures were also more highly associated with physical loading and familial aggregation, further supporting their validity. Age and physical loading had higher associations with the sagittal than the axial measures and with upper rather than lower lumbar discs. Adjustment of signal-based measures by cerebrospinal fluid is critical and increased the associations between age and the measures by 2- to 10-fold.

CONCLUSION

: The new signal-based measures show promise in their potential to better capture and perhaps distinguish aspects of disc degeneration than current assessment methods using standard MRI. Their use may enhance research on potential determinants of disc degeneration.

ISSLS prize winner: microstructure and mechanical disruption of the lumbar disc annulus: part I: a microscopic investigation of the translamellar bridging network

STUDY DESIGN

Microstructural investigation of interlamellar connectivity.

OBJECTIVE

To reveal the macro and micro structure of the translamellar bridging network in the lumbar annulus.

SUMMARY OF BACKGROUND DATA

Contrary to the view that there is minimal interconnection between lamellar sheets, experimental data reveal a significant contribution to the material behavior of the annulus from interactions between fiber populations of alternating lamellae. Recent microstructural studies indicate a localized rather than a homogeneous or dispersed mode of interconnectivity between lamellae.

METHODS

Anterior segments of ovine lumbar discs in 2 age groups were sectioned along the oblique fiber angle. A 3-dimensional picture of the translamellar bridging network is developed using structural information obtained from fully hydrated unstained serial sections imaged by differential interference contrast optics.

RESULTS

A high level of connectivity between apparently disparate bridging elements was revealed. The extended form of the bridging network is that of occasional substantial radial connections spanning many lamellae with a subsidiary fine branching network. The fibrous bridging network is highly integrated with the lamellae architecture via a collagen-based system of interconnectivity.

CONCLUSION

This study demonstrates a far greater complexity to the interlamellar architecture of the disc annulus than has previously been recognized. Our findings are clearly relevant to disc biomechanics. Significant degrading of the translamellar bridging network may result in annular weakening leading potentially to disc failure. Most importantly this work opens the way to a much clearer understanding of the microanatomy of the disc wall.

Outcome following lumbar disc surgery: the role of fibrosis

BACKGROUND

Failed-back surgery syndrome remains a challenge for spinal surgeons. It can be related to several causes, including poor surgical indication, misdiagnosis, surgical technique failure, spondilodiscitis and fibrosis. Fibrosis has been associated with a poorer outcome in lumbar disc surgery, although its role in the generation of symptoms is not yet clear. In this study, the authors have analyzed any possible correlation between the clinical outcome and the degree of fibrosis.

METHOD

Forty consecutive patients were enrolled in a prospective study. All of them had operations in the lower lumbar disc in a single level for the first time. Three months after the operation they were submitted to clinical outcome evaluations and questionnaires, including Numeric Pain Rating scales (NPR) for lumbar and leg pain, the McGill Pain Questionnaire, The Quebec Back Pain Disability scale (QBPD) and Straight Leg Raising test. These data were correlated with the degree of fibrosis as revealed by Magnetic Resonance Imaging (MRI).

FINDINGS

After 3 months, the NPR values for lumbar and leg pain ranged from 0 to 8 (mean 2.32 and 1.67 respectively). The values of the post-operative QBPD scale ranged from 1 to 71 (mean 25.9). Every patient showed a varied degree of fibrosis on MRI. However, statistical analysis depicted no significant correlation between fibrosis and a poorer clinical outcome for pain and disability.

CONCLUSIONS

The authors found no correlation between excessive fibrosis with lumbar and leg pain, disability or straight leg resistance. The role of fibrosis in the generation of symptoms in patients who have had lumbar disc surgery should be reevaluated.

The prevalence and characteristics of thoracic magnetic resonance imaging findings in men

STUDY DESIGN

A cross-sectional study of thoracic magnetic resonance image (MRI) findings.

OBJECTIVE

To examine the prevalence of different thoracic MRI findings for T6-T12 and their associations with age and one another by level.

SUMMARY OF BACKGROUND DATA

There is a dearth of descriptive epidemiology of thoracic MRI findings in the general population.

METHODS

Thoracic MRIs of 524 men were assessed qualitatively and quantitatively for a variety of findings, including disc bulging, height and signal, vertebral deformities, endplate irregularities, osteophytes, and hemangiomas. Descriptive statistics, correlation coefficients and STATA's survey analysis were used.

RESULTS

In the lower thoracic spine, 5.4% to 9.5% of the discs, depending on level, were qualitatively assessed as moderately to severely narrowed. Anterior bulging was more common than posterior, which was relatively rare and mild when present. Signal was lower in the midthoracic than lower discs. At least 1 moderate or severe vertebral deformity was found in 6.1% of the subjects, suggesting fracture, and hemangiomas were identified in 2.3% of subjects. Disc signal correlated most highly with age (r = 0.31-0.42). Qualitatively assessed disc height narrowing (r = 0.29-0.46) and quantitative disc height (r = 0.11-0.29) were associated with disc signal. Upper and lower endplate irregularities were associated with one another (r = 0.17-0.32), as were bulging and osteophytes, anteriorly (r = 0.35-0.61) and posteriorly (r = 0.26-0.45).

CONCLUSION

Degenerative MRI findings beyond a mild grade were not commonly observed in the thoracic spine among 35-70-year-old men. Posterior bulges, in particular, were rare. The highest correlation with age existed for disc signal. Different MRI findings were associated with one another, but the magnitude of association varied by level. The effects of individual judgments and disc level on prevalence rates were apparent.

Vertebral endplate signal changes (Modic change): a systematic literature review of prevalence and association with non-specific low back pain

The prevalence of "vertebral endplate signal changes" (VESC) and its association with low back pain (LBP) varies greatly between studies. This wide range in reported prevalence rates and associations with LBP could be explained by differences in the definitions of VESC, LBP, or study sample. The objectives of this systematic critical review were to investigate the current literature in relation to the prevalence of VESC (including Modic changes) and the association with non-specific low back pain (LBP). The MEDLINE, EMBASE, and SveMED databases were searched for the period 1984 to November 2007. Included were the articles that reported the prevalence of VESC in non-LBP, general, working, and clinical populations. Included were also articles that investigated the association between VESC and LBP. Articles on specific LBP conditions were excluded. A checklist including items related to the research questions and overall quality of the articles was used for data collection and quality assessment. The reported prevalence rates were studied in relation to mean age, gender, study sample, year of publication, country of study, and quality score. To estimate the association between VESC and LBP, 2 x 2 tables were created to calculate the exact odds ratio (OR) with 95% confidence intervals. Eighty-two study samples from 77 original articles were identified and included in the analysis. The median of the reported prevalence rates for any type of VESC was 43% in patients with non-specific LBP and/or sciatica and 6% in non-clinical populations. The prevalence was positively associated with age and was negatively associated with the overall quality of the studies. A positive association between VESC and non-specific LBP was found in seven of ten studies from the general, working, and clinical populations with ORs from 2.0 to 19.9. This systematic review shows that VESC is a common MRI-finding in patients with non-specific LBP and is associated with pain. However, it should be noted that VESC may be present in individuals without LBP.

Factors associated with lumbar intervertebral disc degeneration in the elderly

BACKGROUND CONTEXT

Lumbar intervertebral disc degeneration (DD) precedes degenerative diseases of the lumbar spine. Various factors in addition to normal aging are reported to be associated with DD, and recently atherosclerosis and risk factors for cardiovascular diseases (cardiovascular risk factors) have received much attention; however, the links between these risk factors and DD are unclear.

PURPOSE

By correlating magnetic resonance images (MRI) with suspected degenerative disc risk factors such as obesity, cardiovascular risk factors, and atherosclerosis, we hope to clarify the factors associated with DD.

STUDY DESIGN/SETTING

An observational study.

PATIENT SAMPLE

Two hundred seventy adults (51-86 years old) who participated in a health promotion program.

OUTCOME MEASURES

DD evaluated based on the signal intensity of MR T2-weighted mid-sagittal images of the lumbar spine.

METHODS

Age, gender, body mass index (BMI), low-density lipoprotein cholesterol (LDLc), triglyceride (TG), glycosylated hemoglobin (HbA(1c)), brachial-ankle pulse wave velocity (baPWV) as an index of atherosclerosis, osteo-sono-assessment index (OSI) calculated from quantitative ultrasound assessment of the calcaneus as an index of bone mineral density (BMD), history of low back pain (LBP), smoking and drinking habits, and physical loading related to occupations and sports were assessed. The univariate relationships between DD and the variables were evaluated, and finally, odds ratios (OR) and 95% confidence intervals (CI) for the associations of each factor with DD were calculated using logistic regression at each disc level.

RESULTS

Aging correlated significantly with DD of L1/2 (OR, 2.14), L2/3 (OR, 3.56), L3/4 (OR, 2.84), and L4/5 (OR, 3.05); high BMI, with L2/3 (OR, 2.98), L3/4 (OR, 3.58), L4/5 (OR, 2.32), and L5/S1 (OR, 3.34); high LDLc, with L4/5 (OR, 2.65); occupational lifting, with L1/2 (OR, 4.25); and sports activities, with L5/S1 (OR, 3.36).

CONCLUSIONS

Aging, high BMI, high LDLc, occupational lifting, and sports activities are associated with DD. The results of this study raise our index of suspicion that cardiovascular risk factors and particular physical loading may contribute to DD; however additional studies are required to further investigate associations between DD and these factors.

Prolonged upright posture induces degenerative changes in intervertebral discs in rat lumbar spine

STUDY DESIGN

Both forelimbs of rats were amputated, and these rats were kept in the custom-made cages that kept the rats in prolonged upright posture. Pathologic changes were observed in the lumbar spine at different time points after the surgery.

OBJECTIVE

To investigate the effect of upright posture on intervertebral discs of rat lumbar spine.

SUMMARY OF BACKGROUND DATA

Previous studies have shown that increased axial forces on the spine can decrease the height of the intervertebral disc, but there are no data to indicate whether or not long-term and repeated assumption of the upright posture could result in degenerative changes.

METHODS

The forelimbs of 30 rats were amputated when they were 1-month old. These rats were kept in the custom-made cages and were forced to stand upright on their hind-limbs and tails to obtain water and food. Normal rats of the same ages kept in regular cages were used as control. The rats were killed at 5, 7, and 9 months after the surgery, and the intervertebral discs samples of lumbar spine were harvested for histologic and immunohistochemical studies. Total RNA isolated from these samples was used for real-time PCR of type II collagen (Col2alpha1), type X collagen (Col10alpha1), matrix metalloproteinase-13 (MMP-13), aggrecan, and disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS-5). RESULTS.: Histologic analysis showed degenerative changes of the intervertebral discs after surgery such as disordered collagen structure of endplate cartilage, fragmentation of annulus fibrosus, and decreased height of disc. Immunostaining revealed decreased protein level of type II collagen and increased protein expression of type X collagen. Real-time PCR showed upregulated expression of MMP 13, ADAMTS-5, and Col10alpha1 mRNA and downregulated mRNA expression of Col2alpha1 and aggrecan.

CONCLUSION

Long-term and repeated assumption of the upright stance accelerates disc degeneration in rats.